Explosionproof switch housing



Patented May 2, 1939 UNITED STATES EXPLOSIONPROOF SWITCH HOUSING Clarence A. Hardage, Syracuse, N. Y., assignor to Grouse-Hinds Company, Syracuse, N. Y., a corporation of New York Application October 12, 1936, Serial No. 105,199 9 Claims. (01.200-168) This invention relates in general to explosionproof switch housings of the type used to house electrical switches, and other apparatus, in hazardous locations, such as in an atmosphere containing inflammable or explosive gases, or other inflammable or explosive materials.

The invention has as an object, a switch housing of the type referred to and of such construction as to effect maximum strength with a minimum of weight.

The invention has as a further object, a novel construction by which the switch, or switches, are conveniently installed in the housing and are detachably secured thereto.

The invention has as a further object, a construction including interchangeable parts to obtain greater flexibility in that by re-arrangement of the parts the housing will accommodate switches of different types and sizes.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawings in which like characters designate corresponding parts in all the views.

Figure 1 is a front plan view of the housing with certain features of the construction being indicated in dotted outline.

Figure 2 is a top end elevational view.

Figure 3 is an axial cross-sectional view.

Figure 4 is a cross sectional view taken on lines 4-4, Figure 1.

Figure 5 is an enlarged, fragmentary view of the reset mechanism and contiguous portion of the housing.

The invention comprises generally, a cylindrical body section formed with conduit receiving apertures and preferably eachend of the cylindrical body being thlreaded internally, a switch support, means carried by the switch support and being cooperable with the inner surface of the body section to detachably secure the switch support thereto, with the support extending through either end of the housing, and end sections threading into the open ends of the body section and forming closures therefor.

The body section I0 is preferably of substantially cylindrical cross section, and is provided with a flattened side I I forming a base which, as here shown, is formed at each side with outwardly curved portions I2, the ends of which are provided with conduit receiving passages I3 which open into the interior of the body section. The outer side of the base H is also formed with a pair of spaced apart lengthwise extending bosses I5 provided with holes I6 to receive screws, or other fastening means, for securing the body section against the wall or other suitable support.

The ends of the cylindrical body portion are here shown as being threaded internally to receive the externally threaded ,ends of the end sections I'I, I8. The end sections II, I8, are of the nature of tubular caps, and may be of any suitable length. As here shown, the end section II is cup shaped in general cross section forming a shallow closure for the opening in one side of the body section. The end section I8 is of appreciable length and not only forms a closure for the opposite end of the body section, but also forms the housing for the switch. The end sections l1, l8, are preferably of similar dimensions in cross section, so that the sections are interchangeable. The body IO may be provided with two shallow end sections similar to H, or two longer end sections as I8, depending upon the size and type of switching apparatus installed in the housing. The body section It is, for rigidity and strength, preferably formed of ferrous metal or alloy, as cast iron, and the end sections, because of their particular construction, may be formed of a lighter metal, such as an aluminum alloy.

It will be observed, from the description thus far, that the device is conveniently installed in the conduit line, and is convenientlywired. If the conduit line is connected into one of the hub portions I2, the wires in the conduit may be conveniently pulled through the large openings in the ends of the body section.

The housing includes a novel structure for detachably mounting the switching apparatus in the housing, or to the body section IE). This permits both the switch and the switch support to be removed from the housing during installation, and the pulling of the wires through the conduit, effecting maximum access for these operations.

The switch support comprises a pair of spaced apart cylindrical members, such as rods or tubes 20, on which are mounted cross members 2|. The cross members are provided at their ends with apertures to receive the rods 20, and provided with opposed bosses 22 threaded to receive set screws for securing the cross members 2| at any desired position along the length of the rods 20. The switch, or switching apparatus, is mounted upon the cross members 2 I, as indicated by dotted outline in Figure 3, and is secured thereto as by screws 24. A shoe member 25 is pivotally mounted upon like ends of the rod members 20. The

ends of the shoe members 25, which are pivoted to the rods 20, are bifurcated and a cross member 26 is arranged with its ends extending into the bifurcation or slot of the shoe members 25, and is provided with an aperture to receive the rod and is provided with set screws, similar to the cross members 2|, to prevent relative endwise movement between the shoe members and the rods 20. The free ends of the shoe members 25 are formed with an arcuate face 21 from which a rib or flange 28 extends, and the free ends of the shoes are connected together by a rod 29, the ends of which are provided with a right and left hand thread respectively, whereby upon rotation of the rod 29, the shoe members 25 are moved toward and from each other.

The inner wall of the body section I0 is provided with a pair of opposed ribs extending radially inwardly. The ribs 30 are comparatively short in length, and formed with arcuate faces 3| against which the arcuate faces 27 of the shoes 25 abut when the switch support is in operative position in the housing. The ribs 30 are also provided with slots 32 extending inwardly from the faces 3| to receive the rib or flange 28 on the shoes 25.

The switch support unit is mounted in the body section If) by inserting the end of the unit, provided with the shoes 25, through'either end of the body with the shoes 25 in alinement with the ribs 35, and rotating the switch unit to bring the flanges 28 into the slots 32.

As shown in Figure 4, a screw 34 is threaded into one of the shoes 25 and contacts one of the ribs 35 to form a stop for the shoe 25. That is, in Figure 4, the switch unit is inserted in the housing and then rotated clockwise until the screw 34 in the right hand shoe 25 coacts with the rib 35. The tie rod 29 is then rotated, effecting outward expansion of the shoe members 25 into engagement'with the faces 3! on ribs 35. The tie rod 29 is provided at each end with flattened surfaces 35 for the reception of a Wrench, or other suitable tool, to eifect turning movement of the tie rod.

- In addition to the tie rod 25, or in lieu thereof, the

ribs 35 may be provided with one or more set screws 36 to secure the shoes 25 in operative posi' tion. Or, the ribs 28, 30, may be drilled to receive a cotter pin 31.

The top or side 40, opposite thebase l l, is flattened, and switch operating mechanism mounted thereon. The switch operating mechanism comprises a manual or hand lever 4| secured to the outer end of rock shaft 42 as by key 43 and clamping screw 44. The rock shaft is rotatably mounted in a bushing 45 which is threaded into the flattened top wall 45 of the body section. The outer end of the bushing 45 is provided with a head portion under which ismounted a quadrant 46. The quadrant 45 is formed with bosses 47 projecting into a recess 48 formed in the top wall 45, and the quadrant is also provided with upturned ear portions 49 which coact with the hexagonal head of the bushing 45, and thus forms a locking member to prevent unintentional removal of the bushing 45 from the housing.

The arcuate portion of the quadrant 46 is provided with adjustable stops 50 with which the lever 4| coacts when shifted into on and off positions. Also, this portion of the quadrant 45 is provided with one or more apertures 5| to receive a lock, whereby the lever may be locked into on, off, or neutral, positions.

The inner end of the rock shaft 42 is provided with a transversely extending flat member 53, and

as here shown the switch handle is of the nature of a cup shaped member 54 provided with diametrically opposed slots 55 to receive the member 53. The manual 4! and quadrant 45 are so adjusted relative to the rock shaft 42 that the switch actuating member 54 and member 53 extend transversely of the housing I 0 when the switch is in ofi position. This permits the switch support unit and switches to be removed from the housing l 5 by relative rotation only when the switch is in the off position. This permits the switch support unit and switches to be removed from the housing i5 by relative rotation only when the switch is in the off position. The member 53 is secured in a slot formed in the enlarged inner end portion 56 of the rock shaft 42, and the shoulder formed at the joinder of the rod 42 and end portion 56 is beveled, and the inner end of the bushing 45 is provided with a complemental bevel. A resilient washer 5? is inserted between the head of the bushing 55 and the hub of the manual 4!, and operates to exert an outward pressure on the rock shaft 4-2 to bring the shoulder of the end portion into engagement with the complemental bevel on the inner end of the bushing 45. The purpose of this structure is to insure at all times a flame tight joint between the rock shaft 42 and the bushing 45.

It will be observed that should an explosion occur within the housing, the inner end 55 of the rock shaft 42 will be pressed tighter against the inner edge of the bushing 45 and thus tend to confine the ignited gases within the housing. This structure is also carried out in connection with the push button reset 58 also mounted in a bushing 59 in the flat upper wall 45 of the body section It. The inner end of the push button 58 is provided with a tapered shoulder 55, and the inner end of the bushing 59 is provided with a complemental taper. A compression spring, not shown, is mounted within the nut 5| on the outer end of the bushing and which tends to move the push button 58 outwardly, see Figure 5.

From the description thus far, it will be observed that the body section lil with the end closures I1, I 8, removed, may be most conveniently installed in the conduit system and the cables or conductors in the conduit pulled into the body section. Subsequently, the desired switches, circuit breakers, or other apparatus, may be mounted upon the cross members 2| and 26, and the switch support and switches quickly and conveniently installed in t. e body section I 5. That is, the switch support is secured in the body section It), but projects outwardly through the end of the body with the switches completely exposed and freely accessible to be wired to the conductors or cables from the conduit line. Subsequently, the end sections 1 1, l8, are threaded into place, and because of the substantially cylindrical formation of the entire housing, it will stand comparatively great internal pressures without necessitating extreme side wall thickness for the housing. The closed ends of the end sections l1, 18, are provided with one or more transversely extending grooves 65. The purpose of these grooves is to receive a pipe or rod for the purpose of exerting sufficient pressure to tightly screw the end sections into the body section H3, or to remove them therefrom. The grooves form corresponding ribs on the inner sides of the ends with pockets or spaces 66 between the ribs. This structure, while serving as a convenient means of rotating the ends l1, l8, adds material additional strength tothe end structure, permitting it to be formed of metals of less tensile strength and weight, such as aluminum.

What I claim is:

1. An explosionproof switch housing comprising a cylindrical body section formed with conduit receiving apertures, said body section being provided with an opening in one end thereof, a switch support insertable in the body section through said opening and being provided with a member movable into and out of engagement with the inner side of said body to detachably secure the switch support thereto, with the support extending axially of the body and outwardly through said opening, means operable to effect such movement of said movable member, and a tubular housing detachably secured to the body section and forming a closure for said opening therein, and enclosing said switch support.

2. An explosionproof switch housing comprising a body section provided with a conduit receiving aperture, and with an opening in one side thereof, a switch support insertable and removable through said opening and being provided with spaced apart shoe members, said shoe members being movable into engagement with the inner surface of said body section to secure the switch support to the body section, with said support extending axially of the body section and outwardly through said opening, means operable to move said shoes into engagement with the body section, and an end closure detachably secured to said body section and forming a closure for said opening.

3. An explosionproof switch housing comprising a body section provided with an opening in one side thereof, a switch support, spaced apart shoe members pivoted at like ends to said support and being movable about their pivots to engage the inner side of said body section, means operable within the body for moving said members about their pivots into engagement with said body section, and a tubular end closure detachably secured to the body section and forming a closure for said opening.

4. An explosionproof switch housing comprising a body section provided with an opening in one side, a switch support insertable in the body section through said opening, means carried by said switch support and cooperable with the inner side of the body section upon relative rotative movement of the switch support and the body section to secure the support to the body, and a tubular end casing detachably secured to the body and forming a closure for said opening.

5. An explosionproof switch housing comprising a body formed with conduit receiving apertures, said body being formed with an opening in one side thereof, a switch support insertable in the body through said opening and being provided with a member movable into and out of engagement with the inner side of said body, means carried by the body and cooperable with said member to detachably secure the same to the body, with the support extending axially of the body and to one side of the axis thereof, and a tubular housing detachably secured to the body and forming a closure for said opening and enclosing said switch support.

6. An explosi'onproof switch housing comprising a body section provided with a conduit receiving aperture and with an opening in one side thereof, a switch support insertable and removable through said opening and being provided with shoe members movable into and out of engagement with the interior surface of the body, means cooperable with the inner surface of the body and said shoe members to detachably secure the same to the body, with the support extending axially of the body and to one side of the axis thereof, the major portion of said switch support projecting outwardly from the body through said opening, and an end closure detachably secured to the body and forming a closure for said opening and enclosing said switch support.

7. An 'explosionproof switch housing comprising a substantially cylindrical body having a flat side for mounting the same on a support, said body having outwardly extending bosses adjacent said flat side, and said bosses being formed with conduit receiving passages opening into the interior of the body, the ends of said body being formed with internally threaded openings, a switch support of less width than the diameter of said openings and being insertable into the body through said openings, movable members mounted on the inner end of said swiflch support and being movable into and out of engagement with the inner surface of said body intermediate its ends, means for detachably and rigidly securing said members to the body, with the major portion of said support extending outwardly through one of said openings, and a tubular housing detachably secured to the ends of the body and forming closures therefor, and one of said housings enclosing said switch support.

8. An explosionproof switch housing comprising a cylindrical body section formed with conduit receiving passages, said body section being provided with an opening in each end thereof, a

switch support, means carried by the switch supi port and being cooperable with the inner surface of the body section intermediate its ends to detachably secure said switch support to the body section, and interchangeable end sections detachably secured to said body section and forming closures for the openings in the ends thereof.

9. A housing for electrical apparatus comprising a main body section provided with conduit receiving apertures and being formed in opposite sides with large circular internally threaded openings, an apparatus support detachably secured at one end within said body section intermediate its ends and extending outwardly through one of said circular openings, a tubular end section threaded in each of said circular openings and being provided with an end closure, and one of said end sections being of sufiicient length to form a housing for said apparatus support and the apparatus supported thereby.

, CLARENCE A. HARDAGE. 

